Packer



`July 7, 1942. 1

`.1. P. BRADNER Filed Feb. 21, 1940 IN V EN TOR.

A TTORNEY Patented July 7., 1942 UNITED .STATES PATENT OFFICE .rames r.Brauner, sen Francisco, oeuf.

Application February 21, 1940,'serie1 N0. 320,148

8 Claims.`

This invention relates to a packer, and especially to that type ofpacker known as a formation lpacke In drilling oil wells it is oftennecessaryto seat a packer in an open hole. This is particularly truewhen a new or different formation is encountered during the drilling ofa well, and it is desired to obtain a sample of oil, if any, in thatstratum or formation. At such times a hole of the required .diameter hasalready been-drilled, and in order to make a test of the formation ahole of relatively small diameter is drilled down into the formation forexploration or testing purposes. This smaller hole is commonly referredto as a rathole At the juncture between the well bore and a rathole atapering seat or square shoulder is formed, the larger diameter of whichis represented by the well bore and the smaller diameter by the rathole.

In drilling both the main well bore and the rathole, it is possible thathigh pressure gas or oil strata may be encountered which would tend toblow the hole. Hence, a heavy drilling fluid, usually called mud isemployed to prevent blowing. This mud illls thev entire well bore andthe rathole, and when a rathole packer, together with a string oftesting tools, is lowered to seal of! the formation and to obtain asample therefrom, the pressure in the rathole or below the packer maydrop considerably while the mud column will maintain its high pressure,thereby tending to leak by the packer and cut the seat of the rathole tosuch an extent that the packer (Cl. 16B-1) loses its seal. For thisreason it is important to drive or force the packer into. the ratholeseat with considerable pressure in order that no leakage may occur, andconsequently great diiculty is often encountered in removing the packerand connected string of testing or sampling tools after a sample hasbeen taken.

The object of the present invention is generally to improve and simplifythe construction and operation of tools of the character described, andparticularly to provide a rathole packer which may be forced or firmlydriven into the rathole seat prior to the taking of a sample, to form asubstantially leakproof seal, and thereafter be readily released andremoved when the sample Ahas been taken. The packer and the toolsemployed in connection therewith are shown by way of illustration in theaccompanying drawing, in which:

Fig. l is a vertical section of a well bore, showing the packer and thetesting tools in position to take a sample from a stratum or formationt0 be tested. A portion of the packer is shown in section in this view.

Fig. 2 is an enlarged vertical longitudinal section of the samplingtool, together with a portion of thestring or tubing from which itissuspended;

Fig. 3 is an enlarged vertical longitudinal section of the ratholepacker;

Fig. 4 is an enlarged view of a packer sleeve;

Fig. 5 is an enlarged cross section of the packer sleeve prior tocontraction; and

Fig. 6 is a similar section showing the packer sleeve after contraction.

In the drilling of oil wells, and in operations incident to testing theproductivity of different formations which are being penetrated, it isdesirable to provide apparatus which may be readily lowered into thewell through the drilling mud contained therein, without the necessityof removal of the mud. Also, it is desirable to seal ofi the formationto be tested from the mud withfrom are removed from thewell, and theentrapped sample of iluid may then be drained out and tested.

The present invention provides an improved form of packer for sealingof! the formation to be tested, and while the packer may beused withdierent types of testing or sampling tools, a suitable form of tool isshown by way of illustration, and will be only briefly described, as acomplete description of its structure will be found in Patent No.2,073,107, entitled "Well testing method and apparatus, issued March 9,1937, to

M. O. Johnston.

Referring to the drawing in detail, A indicates a packer; B, a mudby-passing valve; C, a main Ivalve; D, a trip valve; E, a portion of theupper drill string or tubing from which the tools are y 55 .have beendrilled, and in order to make a test of the formation. a hole J ofrelatively small diameter isdrilied down into the formation. Thissmaller hole is commonly referred to as a rathole. At the Junctionbetween the main well bore or hole and the rathole, a tapering seat K isformed, or a shoulder, and it is this seat into which the packer A isforced when the formation is to be sealed oil from the mud in the welland the strata above. a

Due to the high pressure exerted on the packer maintained until thepacker reaches its seat, when it will be forced tightly into the seat bythe weight and downward pressure of the tool string.

by the hydrostatic head of the mud above the packer, particularly in adeep well, there is considerable danger of mud leaking by the packer andcutting away the rathole seat, this being particularly true if aconsiderable pressure reduction takes place -below the packer while asample is being taken. It is for this reason that the packer must ber-mly seated during the taking of a sample, and due to the rm seating itoften happens that considerable trouble is encountered when the packeris to be removed. The trouble of removal will be entirely overcome bythe use of the packer here illustrated. The packer consists of a headmember 2 which is secured by means of a threaded coupler 3 to the lowerend of the Valve body B containing vthe mud by-passing valve. Secured tothe head 2 by a threaded connection 4 is a tube 5, and slidably mountedthereon is a sleeve 5 which carries the packer A. The sleeve 6 has aflange I formed at its upper end to act as a retainer for a series ofpacking discs 8 which are slipped over the sleeve. The lower end of thesleeve is threaded to receive a washer 9 and a nut I0, and by these thepacking discs are held in co pressed condition. A

Formed in the sleeve G intermediate the flange 'I and the lower'threaded end are a series of slots II which serve the function ofpermitting contraction or reduction in the diameter of the sleeve, andconsequently the packing discs 8. when the packer is to be removed fromits seat, as will hereinafter be described. The upper end of the tube 5(see Figs. 1 and 3) presents an exterior diameter which snugly fits theinterior of the sleeve 6, thus preventing contraction oit' the sleeve i.The lower end of the tube, on the other hand, is reduced in diameter, asindi cated at 5a, to permit contraction of the sleeve when the packer isto be released and removed from its seat. To permit such contraction asheretofore described, the tube 5 is pulled upwardly in the sleeve untila collar I2 on the lower end thereof engages the lower` end of thesleeve 5. When this position is assumed, the reduced diameter of thetube 5a will register with the slots II, permitting the sleeve wall toyield inwardly and assume the contracted position shown in cross sectionin Fig. 6. The reduction in diameter thus provided will be considerable,and the packer, which has previously been firmly driven, and which wouldpresent serious difficulty when removal thereof is attempted, is in thisinstance readily removed due to the amount of contraction provided.

In actual practice, when the rathole has been drilled and a sample is tobe taken, the packer A, the mud by-passing valve B, the main valve C andthe trip valve D are assembled and connected at the surface, and bymeans of the drill string or tubing E is lowered into the well. Duringthe lowering operation the packer A will assume the position shown inFig. 3, as it is held in this position by a pair of hooked pins securedto the collar 2, and this position will be During the lowering movementandwhile the packer is being forced into its seat the larger upper end 5of the tube is in register with the slotted sleeve l, and as the largerend of tube 5 snugly fits the interior of the sleeve, contraction cannot take place while the packer is forced into the seat.

During the lowering movement through the mud, 4bil-P2185 valve B isautomatically maintained in open position, that is, with the ports I5 inregister with the annular space I6 and the outlet .ports I1, so that mudmay pass freely through the anchor tube I8, the tube 5. the head 2, thepassage I9, and portsv I1 and I5, but when the packer becomes seated,sleeve 2l in -which the-ports I5 are formed telescopes and vmovesdownwardly in the valve body B to the position shown in Fig. 2, therebyclosing the bypass. Valves C and D are maintained in closed positionduring thel lowering movement, but when the packer has become firmlyseated, valve C opens automatically on taking the weight of the drillstring; valve D, on the other hand, is opened by manipulation from thesurface, and fluid from the formation to be tested is thus free to flowup through the anchor tube, the connected tube 5 and the by-pass valve',which is now closed. 'I'hereafter the fluid flows through' the mainvalve C into the intermediate string or tubing F, which is of suflicientlength and capacity to entrap and retain the quantity of fluid requiredfor testing or sampling Ipurposes.

After the sample has been taken the whole string of tubing E, togetherwith the sampling tool and packer, will have to be raised and removedfrom the well. 'I'he moment raising movement commences, valve C closes,thereby entrapping the fluid sample; the by-pass valve B opens, and head2 through means of the hooked pins 30 will exert an upward pull on thepacker, but as this is firmly seated the hooks will yield or straightenout, thereby releasing the packer and permitting the tube 5 to be pulledupwardly through the packer until the collar I 2 engages the same. Thereduced diameter 5a of the tube now registers with the the pullcontinues the slotted wall of the sleeve yields and contracts, therebypermitting the packing discs to contract, and the packer is thusreleased with comparative ease. and the entire string of tubing andtools is readily removed.

When the packer is being forced into the rathole seat the packinggaskets or discs l tend to assume a dished or curved shape, such asindicated by the dotted line a-a in Fig. 3. Hence when the packer isbeing removed they tend to straighten out and thus exert an inward forcewhich is utilized to collapse or contract the slotted sleeve 6. In Figs.5 and 6 the sleeve is shown as surrounded by two overlappingsemi-circular sections of thin sheet metal, as indicated at 25 and 25.These sections of metal cover the slotted packer sleeve 6, and asvhooked pins are made of heavy wire or smalldiameter rods which haveample strength to secure the packer to the head 2 during the loweringoperation, but when the packer is to be released and pulled out of itsseat, they are ineffective to do so, as the hooked ends will yield y andpull out of the hole formedl in flange 1, thereby permitting upwardmovement of tube 5 and transfer of the entire pulling operation to in gmedium I and the slotted sleeve 8, is to bev treated and considered as aunit; this packer l being characterized by the provision of acontractible seal with a tapering exterior and having a central passagein it, of uniform diameter throughout the length of the packer.Essential to fthe operation of the packer is the rigid tubewhichpresents two diameters, one which snugly fits-the packer to preventinward movement of the same when being seated in the formation,

and a second portion of reduced diameter to provide an annular space sothat the packer may contract when it is to be removed from theformation. The packing medium A is at no time expanded. It is providedwith a tapering exterior surface, which is set by the great weight ofthe tool string into the seat a-a of the formation to form a seal. Whenso seated, the packer is compressed, and, therefore, tends to yieldinwardly, or in other words, to become reduced in diameter. Suchreduction in diameter must be properly limited when thepacker is beingset or seated into the formation to insure a tight seal. To limit thistendency to inward yielding movement while the packer is in itsoperative positioii in the well, the enlarged diameter portion of thetube I ts snugly within the packer.

When the packer is to be removed, the rigid tube is pulled upwardly andthe portion 5a of smaller diameter will thus enter the central passageof the packer. There will thus be provided an annular space around theportion 5a which will permit inward contraction of the packer, and

larger or the smaller diameter portion within the sleeve.

2. A well packer of the character described comprising an elongatedsleeve surrounded by a packing medium, said sleeve being of uniformdiameter throughout its length and `being provided with a plurality ofslots which extend throughout the greater portion of its length to forma yieldable wall. a rigid tube extending through the sleeve and slidabletherein, said tube presenting a uniform diameter throughoutapproximately half of its length which iltsthe interior of the sleeve toprevent yielding of the sleeve wall, and a second portionvof reduceddiameter throughout the remainder of its length, which provides space topermit inward yielding of the sleeve wall. and means for connecting oneend of the rigid tube with a tool string whereby it may be manipulatedtoposition either the larger or the smaller diameter portion within thesleeve. Y

3. A well packer of the character described comprising an elongatedsleeve, said sleeve being provided with a plurality of spaced slotswhich extend substantially from end to end of the sleeve, a iiange onone end of the sleeve, a nut on the opposite end, a plurality of packingdiscs carried by the sleeve, and maintained under compression by theflange and nut, a rigid tube extending through the sleeve and slidabletherein, said tube presenting a diameter throughout a portion of thelength which lits the interior of the sleeve to prevent yielding of thesleeve wall, and a second portion of reduced diameter which providesspace to permit yielding oi the sleeve wall, and means for connectingone-end of the rigid tube with a tool string whereby it may be therebypermit it'to be released when it is to be removed.

While certain features of my invention have been more or lessspecifically described and illustrated I nevertheless wish it understoodthat changes may be resorted to within the scope of the appended claims.

Having thus described and illustrated my invention, whatV I claim vanddesire to secure by Letters Patent is:

l. A well packer of the character described comprising an elongatedsleeve surrounded by a packing medium, said sleeve being of uniformdiameter throughout its length and having a yieldable annular wall, arigid tube extending through` the sleeve and slidable therein, said tubepresenting a uniform diameter throughout approximately half of ,itslength which fits the interior of the sleeve to prevent yielding of thesleeve wall, and a second portion of reduced diameter throughout theremainder of its length, which provides space to permit .inward yieldingof the sleeve wall, and means for connecting one end of the rigidtubewith a tool string whereby it may be' manipulated to position eitherthe manipulated to position either the larger or the smaller diameterportion within the sleeve.

4. A well packer of the character described comprising an elongatedsleeve, said sleeve being provided with a plurality of spaced slotswhich extend substantially from end to end of the sleeve, a ilange onone end ofthe sleeve, a nut on the opposite end, a plurality of packingdiscs carried by the sleeve, and maintained under compression by theange and nut, a rigid tube extending through the sleeve and slidabletherein, said tube presenting a diameter throughout a portion of thelength which ts the interior ofwhen a raising movement is imparted tothe tool l string.

5. A well packer of the character described comprising an elongatedsleeve surrounded by a packing medium, said sleeve having a yieldableannular wall, a rigid tube extending through the sleeve and slidabletherein, said tube presenting a diameter throughout a portion of itslength which fits the interior of the sleeve to prevent yielding of thesleeve wall, and a second portion of reduced diameter which providesspace to permit yielding of the sleeve wall, a head member secured toone end of the rigid tube to connect the tube with la tool string,whereby it may be manipulated to position either the larger or thesmaller diameter portion within the sleeve, and

a detachable connection formed between the head member and the sleeve.

6. lA well packer of the character described comprising an elongatedyieldable packing member permissibly yieldable under external pressure,

' said member presenting an exterior tapering aurface and having aninterior central passage of uniform diameter throughout its length, arigidA tube extending through the central passage of the 'packing memberand being slidable therein, said tube presenting a uniform diameterthroughout approximately half its length, to ilt the central passageofthe packing member and to prevent yielding of the said member, and asecond portion of reduced diameter throughout the remainder of itslength, which provides space to permit inward yielding-of the packingmember.,

v -contraction of the packing medium when seated in position in thewell, andl having the. remaining portion of its length of l uniform butsubstantially less diameter than the in ner diameter of said packingmember tol permit reduction in diameter and ready removal ofsaid packerwhen the tube is positioned with said portion o f lesser diameter withinthe packing member.

8. In a well packer having an elongated, radially contractible sleevesurrounded by a conical packing medium which is yieldable under.external pressure, a rigid tube extending through said sleeve andslidable therein, la cylindrical portion of the tube making a'snug twith the inner diameter of said sleeve, another cylindrical portion ofits length being substantially less in diameter than the inner diameterof said sleeve, a head member secured to one end of said tubeforconnection to a tool string and arrangedfor axial movement of saidtube within said sleeve, and a detachable connection formed between saidhead member and said sleeve, said connection being broken on the upwardmovement of the tube and permitting said sleeve to contract about theportionof lesser diameter of the tube by external pressure when saidlesser diameter tube portion is moved into the space within the packingmember'.

JAMES r. BRADNER.

